E'ther

[Gk. upper air.] A medium of extreme tenuity, which is a umed to pervade all space, and the interstices between the molecules of all bodies, whether solid, liquid, or gaseous. It is the medium by means of which light, heat, electri¬ city, and magnetism are transmitted, it being claimed that diffused matter cannot convey these forces, and that a very rare substance, differing in character, is needed. Sulphuric ether is ob¬ tained by distilling strong alcohol and sulphuric acid, and is an exceedingly volatile and inflamable body, di olving fats, resins, and oils, and useful in removing grease stains. It is also used as an anaesthetic.